Mattress

ABSTRACT

A mattress comprises a sealed outer casing within which is mounted a resilient support formed by a composite foam core. At least an upper portion of the resilient support is formed by a visco-elastic foam. A vent is provided in a side wall of the casing and is covered by a filter which prevents ingress of bacteria into the cover. A flap is mounted on the cover and in use extends down over the vent to prevent the filter being damaged by fluids.

BACKGROUND OF THE INVENTION

The invention is particularly related to a mattress which is suitablefor use in medical applications for the improved comfort of patients whoare confined to bed for long periods of time. Such patients often sufferfrom bedsores due to the concentration of pressure in regions where thepatient's body touches the mattress, particularly in the regions of theshoulders, hips and heels. Another problem arising in medicalenvironments is the possibility of infection of the mattress withbacteria which could subsequently infect a patient.

The present invention is directed towards overcoming these problems.

SUMMARY OF THE INVENTION

According to the invention there is provided a mattress, comprising anouter casing within which is mounted a resilient support, wherein thesupport is sealed within the casing and said casing has an air vent in aside wall of the casing. Thus, conveniently the casing can be formedwith welded seams without ballooning of the casing. Further, the ventallows the mattress to breathe.

In a particularly preferred embodiment at least an upper portion of theresilient support is formed by a visco-elastic foam. Advantageously theviscoelastic slow foam or memory foam has a tendency to mould itselfinto the shape of the body lying on the foam layer, thus providing aneven distribution of pressure over the body of the patent and thusminimising localised high pressure points.

In a preferred embodiment, a filter is mounted across the air vent toprevent the ingress of bacteria to an interior of the casing.

In another embodiment the filter has pores for through-passage of air,said pores being sized to trap any particle greater than 1 micron insize. As bacteria typically attaches to particles over 6 microns in sizeand the filter blocks the passage of any particle greater than 1 micronin size, the filter effectively prevents ingress of bacteria into thecover.

In a further embodiment a flap is mounted on the cover, the flap beingfixed to an exterior of the cover above the vent and extendingdownwardly over the vent. This advantageously protects the vent andfilter being damaged by fluid such as when cleaning the mattress forexample.

The cover is preferably of an elastic material which is stretched overthe foam core. Additional anti-bacterial, fungistatic protection may beprovided for the foam core and for the cover if desired.

In a preferred embodiment of the invention at least portion of the foamlayer has a profiled area comprising projections and hollows at an uppersupport surface of the foam layer.

In a particularly preferred embodiment said profiled area is at a lowerend of the foam layer forming a heel support region of the foam layer.This advantageously provides extra pressure reduction in the heel areaof a patient when the mattress is in use.

In another embodiment the projections are of generally flat-toppedpyramid shape arranged in a chequered formation with hollows formedtherebetween.

In another embodiment the visco-elastic foam has a density in the range60-95 kg/m³. Most preferably the density of the visco-elastic foam is 85kg/m³.

In a particularly preferred embodiment, the support is provided by amulti-layered support core comprising the viscoelastic foam top layermounted on at least one bottom layer of foam having a greater resiliencethan the visco-elastic foam. This provides added rigidity and support tothe core.

In a particularly preferred embodiment, the bottom layer comprises acombustion modified high resilient foam.

Preferably the casing is of a stretchable elastic material.

In another embodiment the resilient support further includes an outerframe mounted about a side of said layers forming an endless side marginabout said layers, said outer frame being formed of a high index foam.

In a particularly preferred embodiment the mattress includes a compositeresilient support having a laminated core with a rectangular bottomlayer and an associated rectangular top layer superimposed on saidbottom layer, a top face of the bottom layer engaging and adhesivelysecured to a complementary bottom face of the top layer, said bottomlayer being formed of a combustion modified high resilience foam andsaid top layer being formed of a visco-elastic foam, said layers beingof equal depth, said core being encircled by an outer frame formed of ahigh index foam which extends about the side faces and end faces of thecore and being adhesively secured thereto, a sealed casing mounted aboutsaid core, said casing being formed of an elastic material stretchedabout the core with overlapping seams of the core being welded togetherto form a sealed enclosure about the core, an opening in said casingforming a vent to allow air passage between an interior and an exteriorof the casing, a filter mounted across the vent and a flap mounted onthe casing covering the vent and being fixed to said casing about aperiphery of the flap above and at each side of the vent leaving adownwardly facing opening between a lower end of the flap and the casingfor air passage to and from the air vent.

In another aspect the invention provides a mattress comprising an outercasing within which is mounted a resilient support, at least an upperportion of the support being formed by a layer of visco-elastic foam,the support having lower end forming a heel support region of thesupport, an upper surface of said heel support region being a profiledarea of projections and hollows. Preferably the projections have aflat-topped pyramid shape.

In another embodiment the support is sealed within the casing and saidcasing has an air vent in a sidewall of the casing. Ideally a filter ismounted across the air vent to prevent ingress of bacteria to aninterior of the casing. Preferably a flap is mounted onto the casing,the flap being fixed to an exterior of the casing above the vent andextending downwardly over the vent, a free edge of the flap definingwith the casing an opening for through passage of air to and from thevent.

In a further aspect the invention provides a mattress comprising anelastic outer casing within which is mounted a resilient support, atleast an upper portion of the support being formed by a layer ofvisco-elastic foam having a density of about 85 kg/m³.

In another embodiment the resilient support has a laminated constructionincluding a rectangular bottom layer and an associated rectangular toplayer superimposed on said bottom layer, a top face of the bottom layerengaging and being adhesively secured to a complementary bottom face ofthe top layer, said bottom layer being formed of a combustion modifiedhigh resilience foam and said top layer being formed by the layer ofvisco-elastic foam.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clearly understood from the followingdescription of some embodiments thereof, given by way of example only,with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a mattress according to the invention;

FIG. 2 is a plan view of a composite foam core of the mattress;

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a perspective, partially cut-away view illustrating themattress;

FIG. 5 is a detail perspective view illustrating a profiled pressurereducing portion of the core;

FIG. 6 is a perspective view of another mattress;

FIG. 7 is a perspective view of a cushion according to anotherembodiment of the invention; and

FIG. 8 is a perspective view of a foam core of the cushion of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, and initially to FIGS. 1 to 5 thereof, thereis illustrated a mattress according to the invention indicated generallyby the reference numeral 1. The mattress 1 comprises a sealed outercasing 2 within which is mounted a resilient support formed by acomposite foam core 3. A vent 4 is provided in a side wall 7 of thecasing 2 and is covered by a filter 5, which prevents ingress ofbacteria into the cover 2. A flap 6 is mounted on the cover 2 and in useextends down over the vent 4 to prevent the filter 5 being damaged byfluids. The flap 6 is attached to the cover 2 along top and side edgesleaving at least portion of the bottom edge open to allow air passage.

The cover 2 is formed of an elastic stretchable material with seams ofthe cover 2 being welded to provide a sealed enclosure for the core 3.

The foam core 3 comprises an upper layer 8 of a visco-elastic materialmounted on and adhesively secured to a lower layer 9 which comprises acombustion modified high resilience foam. The upper layer 8 has a topsurface 10 upon which a patient is supported in use.

A lower end of the upper layer has an anatomic profiling region 12 inwhich material has been removed from the layer 8 to provide a serious ofprojections 14 and associated hollows 15 arranged in a chequeredconfiguration. The projections 14 have a generally pyramidal shapehaving a square flat top 16 which is substantially flush with thecontinuous portion of top surface 10 at an upper end of the upperlayers. Side walls 17 slope downwardly and outwardly of each side of thetop 16 defining hollows 15 or voids between the projections 14. In thiscase the hollows 15 extend roughly one half of the depth of the upperlayer 8. The depth of both layers 8, 9 is typically about 7 cm. Theupper visco-elastic foam layer 8 has a density of 85 kg/m³.

For added support to the core 3 an outer frame 20 is provided comprisingside pieces 21 glued to each side of the layers 8, 9 and end pieces 22glued across the ends of the layers 8, 9. The frame 20 is formed from ahigh index foam material.

In use, the mattress 1 is mounted on a bed with the upper layer 8 ofvisco-elastic foam uppermost When a patient lies on the mattress 1 theupper layer 8 tends to deform to closely conform to the contour of thepatient's body to gently support and evenly distribute the weight of thepatient over a wide area. Further, the profiled region 12 on which thepatient's heels rest provides extra pressure reduction in the heel areato reduce the risk of pressure sore development in this area of thebody.

The flap which covers the filter and vent does not have to extend fullyacross the side of the casing and may simply extend over the vent andfilter.

It will be noted that the cover can be easily cleaned. Further, as thecover 2 is sealed bacteria cannot impregnate the mattress. The vent andfilter allows the mattress to breathe when a person lies on or gets upfrom the mattress and prevents ballooning of the sealed casing.

It will be appreciated that all the foams used are treated so that theyare flame retardant to British Standard SI 1324.

Referring now to FIG. 6, there is shown another mattress 30 comprisingan outer cover 31 surrounding a foam support core 32 formed by threelayers of foam material comprising an upper layer 33 of visco-elasticfoam, an intermediate layer 34 and a lower layer 35 of foams of greaterresilience than the visco-elastic foam.

The term “mattress” as used in this patent specification can also betaken to include cushions of similar construction. For example,referring to FIGS. 7 and 8, there is shown a cushion 40 according toanother embodiment of the invention. The cushion 40 comprises an outercover 41 having an opening closed by a concealed zip 42 along one edge,within which is mounted a foam support core 43. The foam core 43comprises an upper layer 44 of visco-elastic foam and a lower layer 45of a combustion modified high resilience foam.

The invention is not limited to the embodiments hereinbefore described,but may be varied in both construction and detail within the scope ofthe appended claims.

1. A mattress comprising an outer casing within which is mounted aresilient support, characterised in that the support is sealed withinthe casing and said casing has an air vent in a side wall of the casing.2. A mattress as claimed in claim 1 wherein at least an upper portion ofthe resilient support is formed by a layer of visco-elastic foam.
 3. Amattress as claimed in claim 1, wherein a filter is mounted across theair vent to prevent the ingress of bacteria to an interior of thecasing.
 4. A mattress as claimed in claim 3, wherein the filter haspores for through-passage of air, said pores being sized to trap anyparticle greater than 1 micron in size.
 5. A mattress as claimed inclaim 1, wherein a flap is mounted on the casing, the flap being fixedto an exterior of the casing above the vent and extending downwardlyover the vent, a free edge of the flap defining with the casing anopening for through passage of air to and from the vent.
 6. A mattressas claimed in claim 1, wherein at least portion of the resilient supporthas a profiled area comprising projections and hollows at an uppersurface of the resilient support.
 7. A mattress as claimed in claim 6wherein said projections have a flat-topped pyramid shape.
 8. A mattressas claimed in claim 6, wherein said profiled area is at a lower end ofthe resilient support forming a heel support region of the resilientsupport.
 9. A mattress as claimed in claim 2, wherein the visco-elasticfoam has a density in the range 60-95 kg/m³.
 10. A mattress as claimedin claim 9 wherein the density of the visco-elastic foam is about 85kg/m³.
 11. A mattress as claimed in claim 1 wherein the resilientsupport includes a bottom layer of a combustion modified high resilientfoam and a top layer of visco-elastic foam.
 12. A mattress as claimed inclaim 11 wherein the resilient support further includes an outer framemounted about a side of said layers forming an endless side margin aboutsaid layers, said outer frame being formed of a high index foam.
 13. Amattress as claimed in claim 1 including a composite resilient supporthaving a laminated core with a rectangular bottom layer and anassociated rectangular top layer superimposed on said bottom layer, atop face of the bottom layer engaging and adhesively secured to acomplementary bottom face of the top layer, said bottom layer beingformed of a combustion modified high resilience foam and said top layerbeing formed of a visco-elastic foam, said layers being of equal depth,said core being encircled by an outer frame formed of a high index foamwhich extends about the side faces and end faces of the core and beingadhesively secured thereto, a sealed casing mounted about said core,said casing being formed of an elastic material stretched about the corewith overlapping seams of the cover being welded together to form asealed enclosure about the core, an opening in said casing forming avent to allow air passage between an interior and an exterior of thecasing, a filter mounted across the vent, and a flap mounted on thecasing covering the vent and being fixed to said casing about aperiphery of the flap above and at each side of the vent leaving adownwardly facing opening between a lower end of the flap and the casingfor air passage to and from the air vent.
 14. A mattress comprising anouter casing within which is mounted a resilient support, at least anupper portion of the support being formed by a layer of visco-elasticfoam, the support having a lower end forming a heel support region ofthe support, an upper surface of said heel support region being aprofiled area of projections and hollows.
 15. A mattress as claimed inclaim 14 wherein the projections have a flat-topped pyramid shape.
 16. Amattress as claimed in claim 14 wherein the support is sealed within thecasing and said casing has an air vent in a side wall of the casing. 17.A mattress as claimed in claim 16 wherein a filter is mounted across theair vent to prevent ingress of bacteria to an interior of the casing.18. A mattress as claimed in claim 16 wherein a flap is mounted on thecasing, the flap being fixed to an exterior of the casing above the ventand extending downwardly over the vent, a free edge of the flap definingwith the casing an opening for through passage of air to and from thevent.
 19. A mattress comprising an outer elastic casing within which ismounted a resilient support, at least an upper portion of the supportbeing formed by a layer of viscoelastic foam having a density of about85 kg/m³.
 20. A mattress as claimed in claim 19 wherein the resilientsupport has a laminated construction including a rectangular bottomlayer and an associated rectangular top layer superimposed on saidbottom layer, a top face of the bottom layer engaging and beingadhesively secured to a complementary bottom face of the top layer, saidbottom layer being formed by a combustion modified high resilience foamand said top layer being formed by the layer of visco-elastic foam.